The invention relates to DC brush motor control system and, more particularly, to a control system to provide variable speed drive for both 12 and 42 volt motors in automobile applications using 12 or 42 volt batteries.
With the shift of vehicle voltage systems from 12V to 42V there will be a need for 42V brush motors. Consequently, the development of 42V DC brush motors may be required for different applications, such as engine cooling and HVAC fan modules, etc. Currently, there is no such motor in serial production. As a result, it is anticipated that the change in voltage will facilitate the need for extensive validation of the higher voltage motors.
At the same time, there exists a need for intelligent variable speed 12V motors with high efficiency. One manner to deal with both scenarios and development risks is to design a 42V motor that can also be used in 12V system. On the other hand, it will be very helpful for validation of the 42V system if the existing 12V motors can be used in the system.
Thus, there is a need to provide a novel DC brush motor control system permitting a variable speed drive suitable to any combination of the 12V and 42V batteries and motors.
An object of the invention is to fulfill the need referred to above. In accordance with the principles of the present invention, this objective is achieved by a system that provides a variable output voltage to a DC brush motor. The system includes a DC brush motor, a DC voltage source, a step-up, and step-down DC/DC converter including a switch. The DC/DC convener is constructed and arranged to step-up and step-down voltage from the source to provide an output voltage to the motor between 0 and 42 volts. The system includes a control unit constructed and arranged to receive an input signal and to control the switch based on the input signal to control the motor.
In accordance with another aspect of the invention a method provides a variable output voltage to a DC brush motor. The method provides a DC voltage of 12 volts. The DC voltage is stepped-down to a first output voltage between 0 and 12 volts, and the DC voltage is stepped-up to a second output voltage between 12 and 42 volts to provide an output voltage range of 0-42 volts. An output voltage within the output voltage range is sent to a 42 volt DC brush motor.
Other objects, features and characteristics of the present invention, as well as the methods of operation and the functions of the related elements of the structure, the combination of parts and economics of manufacture will become more apparent upon consideration of the following detailed description and appended claims with reference to the accompanying drawings, all of which form a part of this specification.